A bucket wheel valve of the type referred to is known from the company journal "Polysius teilt mit" No. 90 (August 1981) page 4, illustration 6.
In this bucket wheel valve hot gas is passed through the flow chamber between the rotor shaft and the cell walls, and therefore even on the outside of the cell walls the surface temperature is so high that the troublesome formation of deposits is avoided.
An object of the present invention is to improve the known bucket wheel valve so that the quantity of hot gas required for heating the bucket wheel valve is minimized.